Summary

The organophophorus compounds CELA S 2957, O [2,5-dichloro-4-(methylthio) -phenyl]-O,O-diethyl-phosphorothioate and CELA K 673, O-[2,5-dichloro-4-(methylthio) -phenyl] -O-ethyl-methylphosphonothioate are new wide-spectrum insecticidal and acaricidal substances. Extensive greenhouse and field tests under moderate climate conditions have shown the efficacy against sucking and biting insects as well as mites. K 673 has also given good control of PO-resistant mites. In all our greenhouse and field tests phytotoxicity never has been observed, except a slight influence on the growth of grapes caused by K 673.